Green Street Power Partners will soon put online its 4.8-megawatt solar array at the intersection of Routes 10 and 202 with Summit Lock Road in Westfield. The company hosted a ceremonial ribbon cutting Friday. It'll be the fourth large-scale solar project in Westfield providing power to Westfield Gas & Electric and its customers, general manger Anthony Contrino said in interview this week. The rates Westfield Gas & Electric pays for the power are a confidential part of its contract with solar developer Green Street power, but he said the price is matched with market rates for power.